As far as the SEO business world is concerned, Google Weather Forecast is considered as more important compared to true weather forecasts. This is why there are now many emerging services that let you stay updated with all the happenings in Google Index.
These “weather forecasts” are based on quite simple principles. This is published by the services monitoring hundreds, thousands, and millions of words. This so-called “weather” depends on numerous changes for the past few hours including all the stormy weather.
Moz.com
MOZ.com has the most basic and most commonly mentioned Google weather forecast for the past 30 days.
The only concern with the prediction is the fact that it is only limited for the past 30 days that make it impossible to compare this with the past major “storms.”
Algoroo.com
Moz forecast issue gets rid of Algoroo and allows tracking of changes for an extended period of time.
Semrush.com
SEMRush is keeping track of the changes according to the category. This is a helpful piece of information because individual categories or segments of the index are rarely targeted.
https://www.semrush.com/sensor/
Rankranger.com
RankRanger is another addition that allows tracking changes at the national level. Many changes to the algorithm of Google are initially introduced in the US and there are several days delay with most default changes in Europe. Several changes happened at the same time for the rest of the countries with some taking months before they appeared or got introduced in other countries.
https://www.rankranger.com/google-serp-features
Searchmetrics.com
“Gainers and losers” by countries – results by domain names:
https://suite.searchmetrics.com/en/research
Serpmetrics.com
Aside from tracking the changes in Bing, this doesn’t matter in most c Central and Eastern European markets yet Bing still has a substantial share of the market of search engines in the US.
Moz list of changes of Google algorithm
After some time largest changes appear in Moz list (confirmed/unconfirmed)